The Mystery of the Flowering Hormone
What if you discovered a chemical that, when sprayed onto the leaves of plants, would induce them to flower?
How much do you think the patent on such a chemical would be worth? Especially to the agricultural and horticultural industries.
And what if I told you that scientific evidence for the existence of such a flower-inducing chemical has been known for nearly 100 years? And that whole scientific careers have been devoted to discovering this chemical…mostly in vain.
The story is true….and the hypothetical flowering hormone was even given a name in 1936 by the Russian scientist Mikhail Chailakhyan. He called it florigen* (derived from Latin for “flower-former”).
When did the story of the elusive flowering hormone florigen begin?
As mentioned in a previous post, unlike animals, plants don’t start out with their “naughty bits” – they have no sexual organs, a.k.a., flowers.
Before flowering, plants grow “vegetatively”, that is, they produce just stems, leaves, and roots.
It’s a very big deal when the transition from a vegetative plant to a flowering plant occurs. This involves the “flipping” of some major genetic “switches”, that is, major changes in gene regulation.
Florigen is apparently the signal that “flips the switch”, that is, it’s the internal chemical signal that triggers the floral transition in plants.
But to understand the physiology of the floral transition, scientists first needed a way to be able to induce flowering in vegetative plants under controlled conditions.
A major breakthrough toward this goal was reported in 1920…and not long after, scientific evidence for the existence of a flowering-inducing signal emerged.
Next-Time: What environmental factors induce the flowering transition in plants?
*More information on florigen can be found at Wikipedia. And for a more scientific discussion of florigen, please see a 2007 review by Jan Zeevaart.
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